odd this was the discription in the naruto wikia
This jutsu makes the target think that they are surrounded by total darkness, allowing the user to attack unseen. Although it negates sight, it does not stop the other senses. In essence, the opponent can sense, hear and smell out the user of the technique and break its effects by landing one hit. In the anime, Tobirama Senju was the one to initiate this technique. In the manga, it was Hashirama Senju.